1. Field of the Invention
The present invention relates generally to attachments of, and a method of attaching, any two components of ultrasonic blades or waveguides, and more particularly pertains to attachments, and a method of attaching, of ultrasonic blades or waveguides to blade tips of ultrasonic surgical instruments.
Typical prior art ultrasonic blades or waveguides are produced from one piece of titanium. Some ultrasonic blades or waveguides of ultrasonic surgical instruments, such as the LCS/CS (Laparosonic(copyright) Coagulating Shears/Coagulating Shears) blade and certain reusable blades, are produced with a titanium tip that is threaded into an aluminum shaft. This threaded attachment requires threaded components which preclude any simple and low cost manufacturing method of producing the titanium tips except by machining them in a relatively expensive machining operation. Such ultrasonic waveguides or blades are expensive to manufacture when they require machining operations to produce threaded connections.
The present invention relates generally to attachments of any two components of ultrasonic waveguides or blades, such as attachments of ultrasonic waveguides or blades to blade tips such as end-effectors, and a method of attachment thereof, which extend the possible geometries of the ultrasonic waveguides or blades while reducing their manufacturing costs and material waste.
2. Discussion of the Prior Art
Ultrasonic waveguides are utilized in many different technical fields, such as in ultrasonic medical instruments, including both hollow core and solid core instruments, which are well known in the art and are used for the safe and effective treatment of many medical conditions. Ultrasonic instruments, and particularly solid core ultrasonic instruments, are advantageous because they may be used to cut and/or coagulate organic tissue using energy in the form of mechanical vibrations at ultrasonic frequencies transmitted to a surgical end-effector. Ultrasonic vibrations, when transmitted to organic tissue at suitable energy levels using a suitable end-effector, may be used to cut, dissect, or cauterize tissue. Ultrasonic instruments utilizing solid core technology are particularly advantageous because of the amount of ultrasonic energy that may be transmitted from the ultrasonic transducer through an ultrasonic waveguide (also known as a blade) to the surgical end-effector. Such instruments are particularly well suited for use in minimally invasive procedures, such as endoscopic or laparoscopic procedures, wherein the end-effector is passed through a trocar to reach the surgical site.
Ultrasonic surgical instruments and devices typically comprise an ultrasonic transducer which converts an electrical signal to oscillatory motion, an ultrasonic waveguide, and an end-effector which amplifies this motion and applies it to tissue being operated on. Ultrasonic vibration is induced in the surgical end-effector, for example, by electrically exciting a transducer which may be constructed of one or more piezoelectric or magnetostrictive elements in the instrument handpiece. Vibrations generated by the transducer section are transmitted to the surgical end-effector via an ultrasonic waveguide or blade extending from the transducer section to the surgical-end effector.
The ultrasonic waveguide or blade can be formed as a solid core shaft which is machined from a monolithic piece of a titanium or aluminum alloy or any other suitable metal, or the device can be constructed with multiple parts, wherein the multiple parts are joined at antinodes, which are points of low vibrational stress, with joints extending perpendicular to the longitudinal axis of the device. In the prior art, the waveguide or blade can be formed integral with a blade tip or end-effector, or the blade tip or end-effector can be attached thereto with a threaded coupling.
Accordingly, it is a primary object of the present invention to provide attachments of, and a method of attaching, components of ultrasonic waveguides or blades, such as to blade tips with a joint or attachment design between the shaft of the waveguide or blade and the blade tip which can be easily assembled together without a threaded connection.
A further object of the subject invention is the provision of inexpensive attachments of, and methods to attach, the shaft of a waveguide or blade to a waveguide tip in an ultrasonic instrument. The attachments and methods connect components of the ultrasonic waveguide, such an ultrasonic surgical blade tip to the shaft of a waveguide or blade which is transmitting ultrasonic energy. The connection method utilizes two or more components which are secured together with the use of metal electroforming technology. The present invention reduces the need for expensive machined threaded connections by utilizing a simple design to connect together two components of an ultrasonic waveguide or blade.
The design of the present invention provides two main features to maintain the blade tip and the shaft of the waveguide or blade centered relative to one another and to tightly secure the two components together during ultrasonic activation. These features are functionally equivalent to threaded connections, but are easier to manufacture and less expensive than threaded connections. The two components, the waveguide or blade shaft and the blade tip, can be secured together by a radial compression fit between the components, or secured together by a ring or sleeve fitted over the connection union/joint between the two parts, wherein the ring or sleeve is circumferentially shrunk down and compressed over the connection union/joint by an electromagnetic metal forming process.
A unique advantage of the present invention is an increase in manufacturing and design flexibility because the components do not need machined threads to facilitate the connection, allowing the components to be produced in a simpler fashion, such as by stamping or forging.
In accordance with the teaching herein, the present invention provides a connection union and method for securing together first and second components of an ultrasonic waveguide or blade. The first and second components of the ultrasonic waveguide or blade are formed as complementary components which engage each other with a complementary fitting. Then a compressed fit over the connection union is formed by an electromagnetic metal forming operation which compressively deforms a female coupling member over the connection union.
In greater detail, the female coupling member can comprise a separate sleeve which is compressed over the connection union by the electromagnetic metal forming operation. Alternatively, the female coupling member can comprise a terminal end of one of the first and second components which includes a longitudinally extending recess which forms an outer circumferentially extending sleeve which is compressed over the connection union by the electromagnetic metal forming operation.
In several embodiments, the first and second components are butted together, and each butted end of the first and second components includes at least one circumferentially extending ridge, around which the female coupling member is deformed during the electromagnetic metal forming operation to form an undercut in the female coupling member.
In several embodiments, one of the first and second components comprises a projecting male terminal end, and the other of the first and second components comprises a complementary female terminal end which forms the complementary fitting with the male terminal end. The complementary fitting can be formed by male and female components forming a conical shaped fitting, a frusto-conical shaped fitting, or a cylindrical shaped fitting.
In one embodiment, the complementary fitting is formed by two identical and complementary sandwich half components which face each other along a plane extending along the longitudinal axis of the connection union. Each of the first and second components includes one half of at least one circumferentially extending ridge, around which the female coupling member is deformed around during the electromagnetic metal forming operation to form an undercut in the female coupling member.
In disclosed embodiments, the first component comprises the shaft of an ultrasonic waveguide or blade and the second component comprises a distal tip end of the ultrasonic waveguide such as an end-effector.